1. Field of the Invention
The present invention relates in general to forward and reverse power control in a mobile telecommunication system, and more particularly to a method and apparatus for forward and reverse power control in a mobile telecommunication system, wherein the transfer of power control data between a multi-mode demodulator board assembly (referred to hereinafter as xe2x80x9cMMDAxe2x80x9d) and multi-user modulator board assembly (referred to hereinafter as xe2x80x9cMUMAxe2x80x9d) installed in a base station is implemented on the basis of an independent power control bus, resulting in the occurrence of no time delay during the power control data transfer.
2. Description of the Prior Art
In a mobile telecommunication system, generally, forward and reverse power control is performed to optimize a cell capacity, solve a near-far problem and corner problem and minimize interferences with neighboring cells so as to obtain a large capacity of speech and a good quality of speech. In other words, because signal transmission from a base station to subscriber terminals is subjected to losses different than respective mobile stations, the output of the base station must be controlled to provide such sufficient signal strength that each subscriber terminal can maintain an appropriate signal quality. The base station can perform such a function by controlling power allocation to each forward traffic channel. On the other hand, a reverse link is influenced by independent fading that is different from the forward link because respective signals are propagated along different paths, resulting in a difference between power levels. Further, a reverse signal from a near mobile station can be received by the base station at a power level higher than that from a far mobile station since it is less in path loss than that from the far mobile station. Such a reverse signal of the higher power level causes a considerable degree of interferences with signals from other mobile stations that are received by the base station at lower power levels. For this reason, the output of a reverse traffic channel must be controlled in such a manner that signals transmitted from all mobile stations in a speech sphere can be received by a receiver of the base station at the same average power level irrespective of propagation losses and locations of the associated mobile stations.
With reference to FIG. 1, there is shown in block form the construction of a conventional apparatus for forward and reverse power control in a mobile telecommunication system. In this drawing, the reference numeral 10 denotes a base station and the reference numeral 20 denotes a mobile station. The base station 10 comprises a radio frequency (referred to hereinafter as xe2x80x9cRFxe2x80x9d) transmitter/receiver unit 11, multi-mode demodulator board assembly (MMDA) 12 and multi-user modulator board assembly (MUMA) 13.
The conventional forward/reverse power control apparatus with the above-mentioned construction employs a dual port random access memory (RAM) system for the forward and reverse power control. Namely, for the forward and reverse power control, the MMDA writes power control data into its own dual port RAM and the MUMA reads the power control data from the dual port RAM at an interval of 10 ms. As a result, a time delay of 10 ms occurs in each transfer of link power control data. Consequently, the power control is reduced in speed, resulting in a loss in power and, thus, degradation in quality of speech of mobile stations.
Therefore, the present invention has been made in view of the above problems, and an objective of the present invention is to provide a method and apparatus for forward and reverse power control in a mobile telecommunication system, wherein the forward and reverse power control can be more rapidly performed, thereby reducing a loss in power and thus enhancing the quality of speech of mobile stations.
In accordance with one aspect of the present invention, the above and other objectives can be accomplished by a provision of a method for forward power control in a mobile telecommunication system which comprises a radio frequency transmitter/receiver unit for performing power control data transmission/reception operations, a multi-mode demodulator board assembly (MMDA) for generating forward power control data, and a multi-user modulator board assembly (MUMA) for adjusting a power level of an associated base station according to the forward power control data generated by the MMDA, the method comprising the steps of (a) allowing the MMDA to analyze a power control command, received by the radio frequency transmitter/receiver unit over a pilot channel, and generate the forward power control data as a result of the analysis; (b) allowing the MMDA to transfer the generated forward power control data to the MUMA over a power control bus; and (c) allowing the MUMA to receive the forward power control data from the MMDA over the power control bus and adjust a power level of the associated base station according to a value of the received forward power control data.
In accordance with another aspect of the present invention, a method is provided for reverse power control in a mobile telecommunication system which comprises a radio frequency transmitter/receiver unit for performing power control data transmission/reception operations, a multi-mode demodulator board assembly (MMDA) for generating reverse power control data, and a multi-user modulator board assembly (MUMA) for receiving the reverse power control data generated by the MMDA and bypassing it to the radio frequency transmitter/receiver unit, the method comprising the steps of (a) allowing the MMDA to compare a reception gain value contained in a power control bit, received by the radio frequency transmitter/receiver unit over a fundamental channel, with its threshold value and generate the reverse power control data as a result of the comparison; (b) allowing the MMDA to transfer the generated reverse power control data to the MUMA over a power control bus; (c) allowing the MUMA to receive the reverse power control data transferred from the MMDA over the power control bus and bypass it to the radio frequency transmitter/receiver unit; and (d) allowing the radio frequency transmitter/receiver unit to receive the reverse power control data from the MUMA and transmit it to a mobile station over the fundamental channel, whereby the mobile station receives the reverse power control data over the fundamental channel and adjusts its power level according to a value of the received reverse power control data.
In accordance with a further aspect of the present invention, an apparatus is provided for forward power control in a mobile telecommunication system comprising a radio frequency transmitter/receiver unit for performing power control data transmission/reception operations, a multi-mode demodulator board assembly (MMDA) for analyzing a power control command, received by the radio frequency transmitter/receiver unit over a pilot channel, and generating forward power control data as a result of the analysis, and a multi-user modulator board assembly (MUMA) for adjusting a power level of an associated base station according to the forward power control data generated by the MMDA, wherein the apparatus further comprises an independent power control bus for connecting a power control data output terminal of the MMDA to a power control data input terminal of the MUMA.
In accordance with a further aspect of the present invention, an apparatus is provided for reverse power control in a mobile telecommunication system comprising a radio frequency transmitter/receiver unit for performing power control data transmission/reception operations, a multi-mode demodulator board assembly (MMDA) for comparing a reception gain value contained in a power control bit, received by the radio frequency transmitter/receiver unit over a fundamental channel, with its threshold value and generating reverse power control data as a result of the comparison, and a multi-user modulator board assembly (MUMA) for receiving the reverse power control data generated by the MMDA and bypassing it to the radio frequency transmitter/receiver unit, wherein the apparatus further comprises an independent power control bus for connecting a power control data output terminal of the MMDA to a power control data input terminal of the MUMA.
In accordance with another aspect of the present invention, a method is provided for forward power control in a mobile telecommunication system which comprises a base station including a radio frequency transmitter/receiver unit for performing power control data transmission/reception operations, a multi-mode demodulator board assembly (MMDA) for generating forward power control data and a multi-user modulator board assembly (MUMA) for adjusting a power level of the base station according to the forward power control data generated by the MMDA, and a mobile station for receiving the forward power control data from the base station and transmitting a power control command to the base station over a pilot channel, the method comprising the steps of (a) allowing the MUMA to determine whether the forward power control is required; (b) returning to the step (a) if it is determined at the step (a) that the forward power control is not required and allowing the MUMA to transmit a power control bit over the pilot channel to the mobile station via the radio frequency transmitter/receiver unit if it is determined at the step (a) that the forward power control is required; (c) allowing the mobile station to receive the power control bit transmitted from the radio frequency transmitter/receiver unit in the base station over the pilot channel, compare a digital gain value contained in the received power control bit with its threshold value, generate the power control command as a result of the comparison and transmit it to the radio frequency transmitter/receiver unit over the pilot channel; (d) allowing the radio frequency transmitter/receiver unit to receive the power control command transmitted from the mobile station over the pilot channel and transfer it to the MMDA; (e) allowing the MMDA to receive the power control command from the radio frequency transmitter/receiver unit, analyze it and generate the forward power control data as a result of the analysis; (f) allowing the MMDA to transfer the generated forward power control data to the MUMA over a power control bus; and (g) allowing the MUMA to receive the forward power control data from the MMDA over the power control bus and adjust a power level of the base station according to a value of the received forward power control data.
In accordance with still another aspect of the present invention, a method is provided for reverse power control in a mobile telecommunication system which comprises a base station including a radio frequency transmitter/receiver unit for performing power control data transmission/reception operations, a multi-mode demodulator board assembly (MMDA) for generating reverse power control data and a multi-user modulator board assembly (MUMA) for receiving the reverse power control data generated by the MMDA and bypassing it to the radio frequency transmitter/receiver unit, and a mobile station for transmitting a power control bit to the base station over a fundamental channel, receiving the reverse power control data transmitted from the radio frequency transmitter/receiver unit in the base station and adjusting its power level according to the received reverse power control data, the method comprising the steps of (a) allowing the mobile station to determine whether the reverse power control is required; (b) returning to the step (a) if it is determined at the step a) that the reverse power control is not required and allowing the mobile station to transmit the power control bit over the fundamental channel to the radio frequency transmitter/receiver unit in the base station if it is determined at the step (a) that the reverse power control is required; (c) allowing the radio frequency transmitter/receiver unit to receive the power control bit transmitted from the mobile station over the fundamental channel and transfer it to the MMDA; (d) allowing the MMDA to receive the power control bit transferred from the radio frequency transmitter/receiver unit, compare a reception gain value contained in the received power control bit with its threshold value and generate the reverse power control data as a result of the comparison; (e) allowing the MMDA to transfer the generated reverse power control data to the MUMA over a power control bus; (f) allowing the MUMA to receive the reverse power control data transferred from the MMDA over the power control bus and bypass it to the radio frequency transmitter/receiver unit; (g) allowing the radio frequency transmitter/receiver unit to receive the reverse power control data from the MUMA and transmit it to the mobile station over the fundamental channel; and (h) allowing the mobile station to receive the reverse power control data transmitted from the base station over the fundamental channel and adjust its power level according to a value of the received reverse power control data.